No...
The 388's mixer section is way beyond an M30, mainly being 8-buss (vs. 4) and 3-band sweep-EQ (vs. 2-band sweep + 1 fixed)... a pretty significant difference, leaning toward the 388.
Then, the tape drive section... is the reverse. A 38's 15 IPS, 1/2" tape drive is double the width and double the speed of the in-built 1/4", 7.5 IPS tape section of the 388. Another significant difference,... breaking the other way (to the 38).
So your analysis is slightly flawed & is more a case of mixing apples & oranges. Regardless, I don't think a dead-mint NIB 388 is worth more than $1000, on any day. However, as a unique and self-contained unit, the 388 is pretty awesome in it's own right. For most classic (cassette) Portastudio fans, the 388 is like a wet dream come true.
A Fostex 812 (8-buss) mixer and A8LR (15 ips) recorder might be considered a roughly equivalent step up from the 388. A Tascam M512 and 38 would be considered a big step up in production quality.
The 388 was an ingenious middle-of-the-road production unit made to be moderately portable & self-contained with respectable sound quality, flexibility & "pro" features (relatively speaking at the time), that was aimed at the jingle-studio or sound-for-film(tv/video) post-production facility, (or small home/project studio),... (I think where space was at a premium & bigger, higher end fidelity would not justify a larger more premium audio recording setup).
Some users regularly warn against the 1-of-a-kind scaled-down format of the 388 vs. the head wear issue, where overall new heads are not available. It's a legitimate cause for concern as time goes on, unless you can find a NOS 388 head somewhere, (like me).
With that being said, it's a fun unit to use, being self-contained does have a particular technical charm, and the sound quality is pretty good. The middle ground between cassette & 1/2",... (some say mid-fi). For $150-$450 it's real fine. YMMV.


